In a small bowl, mix the cumin, smoked and sweet paprika, pepper, ginger, allspice, curry powder, sumac, and Aleppo pepper (if using). Set aside.
Heat the oil in a Dutch oven, or other large pot, over medium heat. Once hot, add the onion, carrots, and celery. Season with a pinch of kosher salt. Cook, stirring often, until softened, approximately 2 to 3 minutes.
Turn the heat down to low, add the garlic and ginger, and stir constantly for 30 seconds.
Add the spice mixture and stir until fragrant, approximately 3 to 5 minutes.
Add the crushed tomatoes and tomato paste. Cook, stirring often, for about 3 minutes.
Add 6 cups of the stock. Increase the heat to medium-high. Taste for any seasoning, especially salt, and adjust as preferred. You will want to taste before simmering because the lentils will be absorbing this liquid. You want it to be flavorful.
Add the lentils, bay leaves and oregano; stir. Place the lid on the pot, about an inch slightly askew. With the heat still on low, cook the lentils until tender and the mixture has thickened and the lentils are soft, approximately 30 to 35 minutes. Some lentils need more cooking time; adjust as needed. If it is too thick for your liking, add more stock as desired. If the sauce is too thin, remove the lid and cook for another 5 to 10 minutes.
Taste and adjust seasonings again if needed.
Sprinkle with cilantro.
Serve warm with pita bread.